As a prevailing wide-viewing angle technology of the thin film transistor liquid crystal display (TFT-LCD), plane electric field technology has the advantages of ultra-wide viewing angle, high aperture ratio and short response time, etc. In the current plane electric field technology, an array substrate is generally manufactured via a 6-time patterning process, and there are too many production processes, which causes a high cost for manufacturing the array substrate; in order to reduce the cost for manufacturing the array substrate, a half tone mask (HTM) or a single slit mask (SSM) could be employed for patterning at the position of a channel, thereby the pattern of an active layer and the pattern of a source-drain metal layer may be formed simultaneously via a one time patterning process, so that the array substrate may be manufactured via a 5-time patterning process, thereby the number of times of production processes may be reduced, and the production efficiency may be improved.
However, in the process in which an array substrate is manufactured via a 5-time patterning process, no separate patterning process is employed to manufacture the pattern of an active layer, the active layer exists under the whole source-drain metal layer except for the channel region; as a result, in the effective display region, the difference between the film height at a data line consisted by the source-drain metal layer and the film height of an adjacent region is large, thus during a rubbing process (at present, it generally employs polyimide solution rubbing to make the liquid crystal molecules be arranged orderly), the regions in the vicinity of the data line on the array substrate are difficult to be rubbed, so that the liquid crystal arrangement in the regions in the vicinity of the data line will be disordered, and light leakage will occur once the region is not covered by a black matrix (BM); however, if a BM is provided to cover this region, the aperture ratio of the pixel will be reduced.